In this video, we learn how to play "21 Guns" by Green Day on acoustic guitar. The chords of the verse are D minor, B flat major, F, and C. Once you have all of these chords, you will be able to start out playing the first verse and have the melody for the song. Move the chords down and up as you play to create a more in depth sound as you are playing. As you go through all of the different verses and chorus, you can add in your own variations to make a more unique song, then sing the normal lyrics to the song.